The invention relates to a permanent-magnet synchronous machine having a rotor and having a stator, which contains a winding system having three winding phases and being constructed with tooth-wound coils.
Such a permanent-magnet synchronous machine is currently used in various embodiments. Examples are described in DE 199 61 760 A1 and in DE 101 24415A1. A current machine type involves a low coil number, for example three, always with a low useful pole pair number, for example of one. Such machines are operated with the basic pole pair number of the stator. Also known are so-called harmonic machines, in which a pole pair number of the rotor corresponds to an integral multiple of the basic pole pair number of the stator. Such multipole synchronous machines have, for example, a useful pole pair number of four, but a higher coil number is always also provided. Thus nine or twelve coils are conventional.
When designing these permanent-magnet synchronous machines, particular attention needs to be paid to an inexpensive implementation and as high a capacity as possible. The capacity is defined as the torque which can be achieved per unit volume. Further criteria which are likewise critical relate to the possibility of operation at a high voltage, i.e. in the region of a few 100 V, and a physical size which is as small as possible. Despite the many available variants, as yet no optimum embodiment is known which satisfies these requirements equally.